Command line to find prime factors up to about 20-digit
echo 3552802610615568256270183415340686890374754815805265297070877658091614272801517644505202336012258749140256804399296266322535479976564515255341171097007 | ecm -n -c 74 11e3
Command line to find prime factors up to about 25-digit
echo 3552802610615568256270183415340686890374754815805265297070877658091614272801517644505202336012258749140256804399296266322535479976564515255341171097007 | ecm -n -c 214 5e4
Command line to find prime factors up to about 30-digit
echo 3552802610615568256270183415340686890374754815805265297070877658091614272801517644505202336012258749140256804399296266322535479976564515255341171097007 | ecm -n -c 430 25e4
Command line to find prime factors up to about 35-digit
echo 3552802610615568256270183415340686890374754815805265297070877658091614272801517644505202336012258749140256804399296266322535479976564515255341171097007 | ecm -n -c 904 1e6
Command line to find prime factors up to about 40-digit
echo 3552802610615568256270183415340686890374754815805265297070877658091614272801517644505202336012258749140256804399296266322535479976564515255341171097007 | ecm -n -c 2350 3e6